function check_null() {
    var telephone = document.getElementById("telephone").value;
    var password = document.getElementById("password").value;
    if (telephone == null || telephone == "") {
        $("#news").html("请输入账号");
        return false;
    }
    if (password == null || password == "") {
        $("#news").html("请输入密码");
        return false;
    }
}